已经创建过作品的用户不允许重复创建

app/controllers/student_work_controller.rb

@@ -13,9 +13,14 @@ class StudentWorkController < ApplicationController
   end
 
   def new
-    @stundet_work = StudentWork.new
-    respond_to do |format|
-      format.html
+    student_work = @homework.student_works.where("user_id = ?",User.current.id).first
+    if student_work.nil?
+      @stundet_work = StudentWork.new
+      respond_to do |format|
+        format.html
+      end
+    else
+      render_403
     end
   end